Clean-up the common sources in dsp.
Clean-up the common sources in dsp.

Change-Id: I1b995e6517e8437127a433dccbb5b2db63e7c3a3

PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,webmproject/libwebp,webmproject/libwebp,PKRoma/libwebp